Photogrammetry is the science of making measurements from photographs. Surveying is the technique and science of accurately determining the terrestrial or three-dimensional space position of points and the distances and angles between them. These points are usually, but not exclusively, associated with positions on the surface of the Earth, and are often used to establish land maps and boundaries for ownership or governmental purposes. Photogrammetry has been used in surveying for a long time and provides a accurate measurement technique for both land based and aerial surveying.
Stereophotogrammetry makes it possible to determine the three-dimensional coordinates of points on an object. These are determined by measurements made in two or more photographic images taken from different positions. Common points are identified on each image. A line of sight can be constructed from the camera location to the point on the object. It is the intersection of these rays that determines the three-dimensional location of the point.
The use of a camera in a surveying instrument, for example, a Total Station, may provide for improved user convenience and new functions. Particularly, a view such as an image or a video feed provided by the camera and shown on a display of the instrument may be used for assisting target selection and for providing the user with an overview of potential points of interest. For a general background of total stations comprising a camera for capturing an image or a video feed of the view towards which the total station is aimed, reference is made to PCT/EP2004/014365 which is incorporated herein in its entirety.
Despite the advances made in surveying instruments, a need exists in the art for methods and systems for performing stereo photogrammetry using surveying.